SUSTAINABILITY A1-A5 Upfront Embodied
B2+B3 Maintenance+Repair (Embodied)
B4 Replacement (Embodied)
B5 Refurbishment (Embodied)
27% 42% 2% 21% 8% B6 Operational
LCA modules included in the analysis We have included LCA modules A1-A5 (‘Cradle to Completion’), B2 (maintenance), B3 (repairs), B4 (refurbishment), and B5 (replacement). We combined LCA modules B2 (maintenance) and B3 (repairs) as they are very much interrelated.
Figure 1: Whole Life Carbon (WLC) emissions profile for a new-build hospital with highly efficient building fabric and heating / air-handling systems.
constrained by parameter assumptions. We have tested the sensitivity to varying key assumptions, and believe that the metrics shown give a good relative and directional representation for the strategic options considered. Although more work is needed to improve confidence in the absolute values of the metrics, we expect this will not significantly change their relative values.
Emissions targets The UK’s emissions reduction targets are a bold 78% reduction over 1990 levels by 20353
(i.e. within the next 13 years). This
level of reduction is needed to keep global warming below 1.5 °C-2 °C, the consensus for minimising the likelihood of key global systems reaching tipping points.4
The
NHS’s emissions reduction targets are set out in Delivering a ‘Net Zero’ National Health Service. These are marginally more ambitious than the UK targets, at an 80% reduction over 1990 levels by 2028 to 2039
DoNothing* (Option 1)
Retrofit* (Option 2)
(i.e., within the next 6 to 17 years), with the date depending on the scope of emissions measured.5
The reductions and timescales
are very ambitious, and will require a step change from how NHS estates are currently managed and (re)developed.
The importance of upfront embodied carbon The first reason to prioritise reducing upfront embodied carbon emissions on new construction is that time is quickly running out. NHS emission reduction targets must be met in 6-17 years, which is a small fraction of a building’s theoretical lifetime of 60 years. The second reason is that embodied carbon forms a substantial share of emissions from new construction or major refurbishments. Our study shows that for a new hospital with a high- performance fabric and high-performance heating and air-handling systems (ASHPs and MVHR), and assuming future decarbonisation of electricity, operational
RetrofitExtend* (Option 3)
Newbuild* (Option 4)
NewbuildFlex* (Option 5)
LCA modules excluded from the analysis Because the relative impacts of LCA modules B1 (Use) and B7 (Operational water use) are negligible, we have excluded them from our analysis. Also, we excluded end-of-life emissions (modules C1-C4) for three reasons: (1) it is a small part of overall WLC; (2) its level is highly uncertain being very far in the future, and (3) its emission is not expected to change the relative calculations for the options introduced in the next section.
carbon (Module B6) can be as low as little more than a quarter, and embodied carbon almost as high as three quarters of lifetime carbon emissions, measured over 60 years. Furthermore, upfront embodied carbon (LCA modules A1-A5) can be more than 40% of lifetime carbon emissions. This is illustrated in Figure 1. The approximately 75/25 split between embodied carbon (construction, repairs, and replacement) and operational carbon (heating, cooling, lighting, appliances) differs from the current rule of thumb assumption of 50/50 for all buildings. This difference arises from factors such as the high proportion of high embodied carbon MEP systems in the fabric of hospitals, and the assumed decarbonisation of electricity into the future.
Redevelopment strategy options Our study considered the impact of different redevelopment strategies for a 30,000 m2
hospital building constructed in
the mid-1980s, built to the standard of the then-prevailing building regulations and clinical space standards (poor compared with current standards). These strategies are represented by five different options:
Option 1 (DoNothing*) – Do nothing / continue ‘as is’; no building upgrades, apart from backlog maintenance.
Option 2 (Retrofit*) – Retrofit; upgrade the building envelope (overclad) and heating systems to current Part L standards, as well as undertaking remaining backlog maintenance.
2022 2032 2042
2035 UK GHG emissions target: 78% reduction from 1990 levels
Figure 2: Comparison of projected 60-year cumulative WLC emissions. 30 Health Estate Journal March 2022 2052 2062 2072
Option 3 (RetrofitExtend*) – Retrofit + extend; Like Option 2, but extend the existing building (at the upper limit of PassivHaus standards for the new build) to enable internal reconfiguration to meet
Cumulative Carbon Emissions 2022 2027 2032 2037 2042 2047 2052 2057 2062 2067 2072 2077
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